Effect of grain size of graphite powder in carbon paper on the performance of proton exchange membrane fuel cell

This work focuses on the effect of graphite powder grain size on the properties of carbon paper and proton exchange membrane fuel cell. In this paper, graphite powders of different grain sizes (0.5–30 μm) are added to carbon paper for proton exchange membrane fuel cell. Furthermore, the carbon paper is subjected to hydrophobic treatment at polytetrafluoroethylene (PTFE). The research results show that with the increase in graphite grain size, the cell performance increases at dry condition, the carbon paper containing 10 wt% PTFE and graphite powder grain size of 30 μm has the best performance, which power density of 892 mW cm −2 and limit current density of 2.40 A cm −2. With the increase in graphite grain size, the cell performance decrease at wet condition, the carbon paper containg 20 wt% PTFE and graphite powder grain size of 0.5 μm has the best performance, which power density of 524 mW cm −2 and limit current density of 1.84 A cm −2. The paper illustrates that reducing the grain size of graphite powder is beneficial to enhancing the water management ability of gas diffuse layer and reduces the performance loss at wet condition, while, increasing the gas transmission resistance and the performance loss at dry condition.